Preparing and Repairing Walls

Use a framing square to mark a rectangular area around a hole. Score the drywall on the lines, then cut through it with a drywall saw or utility knife. Pry out the damaged area or knock it into the wall recess.

Cut 1x3 boards about 6 inches longer than the area to be patched. Insert the boards into the recess and cinch them on one side to the rear of the drywall with 1-inch screws. Repeat for the other side. These cleats will keep the drywall patch from falling into the wall.

Cut a drywall patch of the same thickness as the rest of the wall and to the dimensions of the repair area. Place it in the recess against the cleats. Use 1-inch screws to fasten the patch to the cleats. Tape the joint around the patch with fiberglass-mesh drywall tape.

Finish the joints by applying a thin coat of drywall compound around the perimeter. Let this coat dry and apply a second coat with a wide drywall knife, feathering the edges until the surface is level with the surrounding wall. Prime this area when you spot-prime minor damage.

Cut damaged pieces from the hole with a wide cold chisel. Plaster is held together with a fibrous binder, so there may be small pieces clinging to the edge of the hole. Remove them and, if possible, angle the edges of the hole so they are wider next to the lath than at the surface.

Brush out the area or vacuum it. Using a spray bottle, moisten the edges of the hole and the lath with water. Don't soak the area; a moderate misting is sufficient.

Apply patching plaster to the damaged area with a wide putty knife, forcing the material slightly into the lath. If the thickness of the plaster is more than 1/2 inch, apply a thin coat first, let it dry, and apply another coat. Thick patches tend to crack if applied all at once.

If the crack is a hairline crack, clean it out with the edge of a putty knife or can opener and dust out the crack with an old paintbrush. Moisten the crack and apply spackling compound.

For wide cracks, use a can opener to scrape plaster from the rear of the edge, making it wider at its bottom than on the surface. This will help hold the patching compound more securely. Clean out the crack and vacuum or dust it with an old paintbrush.

Use a spray bottle to moisten the interior of the crack and pack joint compound or thinset into the recess with a wide putty knife or drywall knife. Press the compound into the recessed edges. When you have filled the crack, draw the putty knife across the surface to smooth it. Allow the compound to dry and reapply if necessary. Sand any rough or high spots smooth with medium-grit sandpaper.

Outline a rectangle larger than the damaged area and score the outline with a utility knife. Use a wide cold chisel to remove the plaster, working from the scored line to the center. Work in small sections; tap gently to avoid cracking the remaining wall. Measure the thickness of the plaster at the edge of the cutout area and, if necessary, attach 1/4-inch plywood strips to the lath so a 1/4-inch drywall patch will be flush with the surface.

Cut a drywall patch to the dimensions of the cutout and apply a 1/4-inch bead of construction adhesive to the shims or lath. Press the patch into the area. Starting at the corners, drive 1-inch drywall screws around the perimeter of the patch. Space the remaining screws about 6 inches apart. Tape the joints with fiber-mesh drywall tape and spread a thin, level coat of drywall compound over the tape. Sand level when dry.